Question on matching numbers

I posted before that I was looking to buy my first luger, and that I wanted it to be a shooter. I've found several in my price range that I'm considering- some all matching, some not. I know that if a numbered part should break it will detract from the value, but my question is how frequently can this be expected to happen? I would expect to shoot 300 rounds a month through the gun at most, and it would be well cleaned and cared for. The loss in value doesn't concern me as much as breaking up a matching piece. I'm not willing to get an all matching gun to shoot if there's a good chance I'll break a part and ruin a piece of history.